Hello guys/gals, i am stuck on this boss. After I survive the first round of attacks by having all four blocks destroyed (one in each corner), the tank loses it's shields, fires missiles at me and chases me around. What do i do here to even get a shot at him ? Can anyone help please ?

You have to basically hop around and guide a missle that the tank shoots to destroy the tank. This is the same strategy as when you had them hit the force fields. You just have to keep moving. Good luck!